The inventive concept relates to nonvolatile memory devices, memory systems comprising nonvolatile memory devices, and methods of programming nonvolatile memory devices.
Semiconductor memory devices can be roughly divided into two categories according to whether they retain stored data when disconnected from power. These categories include volatile semiconductor memory devices, which lose stored data when disconnected from power, and nonvolatile semiconductor memory devices, which retain stored data when disconnected from power. Examples of volatile memory devices include dynamic random access memory (DRAM) and static random access memory (SRAM). Examples of nonvolatile memory devices include resistive random access memory (RRAM), phase-change random access memory (PRAM), and flash memory.
Due to a persistent increase in the demand for nonvolatile data storage, researchers are engaged in continual efforts to improve various aspects of nonvolatile memory devices, such as storage capacity, performance, reliability, and others.